BÉRYLLIUM

introduction

Numéro atomique: 4
Groupe: 2 or II A
Poids atomique: 9.012182
Période: 2
Numero CAS: 7440-41-7

Classification

chalcogènes
Halogène
Gaz rare
lanthanides
actinides
Rare Earth Element
Groupe Platine Métal
Transuranium
Pas d'isotopes stables
Solide
Liquide
Gaz
Solide (prédit)

La description • Usages / Fonction

Discovered as the oxide by Vauquelin in beryl and in emeralds in 1798. The metal was isolated in 1828 by Wohler and by Bussy independently by the action of potassium on beryllium chloride. Beryllium is found in some 30 mineral species, the most important of which are bertrandite, beryl, chrysoberyl, and phenacite. Aquamarine and emerald are precious forms of beryl. Beryl (3BeO · Al2O3 · 6SiO2) and bertrandite (4BeO · 2SiO2 · H2O) are the most important commercial sources of the element and its compounds. Most of the metal is now prepared by reducing beryllium fluoride with magnesium metal. Beryllium metal did not become readily available to industry until 1957. The metal, steel gray in color, has many desirable properties. It is one of the lightest of all metals, and has one of the highest melting points of the light metals. Its modulus of elasticity is about one third greater than that of steel. It resists attack by concentrated nitric acid, has excellent thermal conductivity, and is nonmagnetic. It has a high permeability to X-rays, and when bombarded by alpha particles, as from radium or polonium, neutrons are produced in the ratio of about 30 neutrons/million alpha particles. At ordinary temperatures beryllium resists oxidation in air, although its ability to scratch glass is probably due to the formation of a thin layer of the oxide. Beryllium is used as an alloying agent in producing beryllium copper which is extensively used for springs, electrical contacts, spot-welding electrodes, and nonsparking tools. It has found application as a structural material for high-speed aircraft, missiles, spacecraft, and communication satellites. It is being used in the windshield frame, brake discs, support beams, and other structural components of the space shuttle. Because beryllium is relatively transparent to X-rays, ultra-thin Be-foil is finding use in X-ray lithography for reproduction of microminiature integrated circuits. Natural beryllium is made of 9Be and is stable. Eight other radioactive isotopes are known. Beryllium is used in nuclear reactors as a reflector or moderator for it has a low thermal neutron absorption cross section. It is used in gyroscopes, computer parts, and instruments where lightness, stiffness, and dimensional stability are required. The oxide has a very high melting point and is also used in nuclear work and ceramic applications. Beryllium and its salts are toxic and should be handled with the greatest of care. Beryllium and its compounds should not be tasted to verify the sweetish nature of beryllium (as did early experimenters). The metal, its alloys, and its salts can be handled safely if certain work codes are observed, but no attempt should be made to work with beryllium before becoming familiar with proper safeguards. Beryllium metal is available at a cost of about $2.50/g (99.5% pure). 1

Propriétés physiques

Point de fusion:2*  1287 °C = 1560.15 K = 2348.6 °F
Point d'ébullition:2* 2471 °C = 2744.15 K = 4479.8 °F
sublimation point:2 
Triple point:2 
Point critique:2 
Densité:3  1.85 g/cm3

* - at 1 atm

Configuration de l'électron

Configuration de l'électron: [He] 2s2
Bloque: s
Plus haut niveau d'énergie occupés: 2
Électrons de valence: 2

Nombres quantiques:

n = 2
ℓ = 0
m = 0
ms = -½

Bonding

Électronégativité (échelle de Pauling):4 1.57
Electropositivity (échelle de Pauling): 2.43
Electron Affinity:5 not stable eV
oxydation États: +2
Fonction de travail:6 5.08 eV = 8.13816E-19 J

ionisation potentiel   eV 7  kJ/mol  
1 9.3227    899.5
ionisation potentiel   eV 7  kJ/mol  
2 18.21116    1757.1
ionisation potentiel   eV 7  kJ/mol  
3 153.89661    14848.8
4 217.71865    21006.7

Thermochimie

Chaleur spécifique: 1.825 J/g°C 8 = 16.447 J/mol°C = 0.436 cal/g°C = 3.931 cal/mol°C
Conductivité thermique: 200 (W/m)/K, 27°C 9
Température de fusion: 12.2 kJ/mol 10 = 1353.7 J/g
Chaleur de vaporisation: 292.4 kJ/mol 11 = 32445.0 J/g
État de la matière Enthalpie de formation (ΔHf°)12 Entropy (S°)12 Gibbs Free Energy (ΔGf°)12
(kcal/mol) (kJ/mol) (cal/K) (J/K) (kcal/mol) (kJ/mol)
(s) 0 0 2.28 9.53952 0 0
(ℓ) 2.88 12.04992 3.95 16.5268 2.38 9.95792
(g) 77.5 324.26 32.55 136.1892 68.5 286.604

isotopes

Nuclide Masse 13 Demi vie 13 Spin nucléaire 13 Énergie de liaison
10Be 10.0135338(4) 1.51(6)E+6 a 0+ 65.47 MeV
11Be 11.021658(7) 13.81(8) s 1/2+ 66.09 MeV
12Be 12.026921(16) 21.49(3) ms 0+ 69.51 MeV
13Be 13.03569(8) .5(1) ns 1/2+ 69.20 MeV
14Be 14.04289(14) 4.84(10) ms 0+ 70.75 MeV
15Be 15.05346(54)# <200 ns 68.57 MeV
16Be 16.06192(54)# <200 ns 0+ 69.19 MeV
5Be 5.04079(429)# (1/2+)# -0.68 MeV
6Be 6.019726(6) 5.0(3)E-21 s [0.092(6) MeV] 0+ 26.95 MeV
7Be 7.01692983(11) 53.22(6) d 3/2- 37.63 MeV
8Be 8.00530510(4) 6.7(17)E-17 s [6.8(17) eV] 0+ 56.50 MeV
9Be 9.0121822(4) STABLE 3/2- 58.24 MeV
Les valeurs marquées # ne sont pas purement dérivées des données expérimentales, mais au moins en partie des tendances systématiques. Spins avec de faibles arguments d'affectation sont entre parenthèses. 13

Abondance

Terre - composés Source: silicates 14
Terre - Seawater: 0.0000056 mg/L 15
Terre -  Croûte:  2.8 mg/kg = 0.00028% 15
Terre -  Total:  45 ppb 16
Planète Mercure) -  Total:  34 ppb 16
Vénus -  Total:  47 ppb 16
chondrites - Total: 0.69 (relative to 106 atoms of Si) 17

composés

Information de sécurité


Fiche signalétique - ACI Alloys, Inc.

Pour plus d'informations

Liens externes:

Les magazines:
(1) Irion, Robert. Origami Observatory. Scientific American, October 2010, pp 48-55.

Sources

(1) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:5.
(2) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:132.
(3) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 4:39-4:96.
(4) - Dean, John A. Lange's Handbook of Chemistry, 11th ed.; McGraw-Hill Book Company: New York, NY, 1973; p 4:8-4:149.
(5) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 10:147-10:148.
(6) - Speight, James. Lange's Handbook of Chemistry, 16th ed.; McGraw-Hill Professional: Boston, MA, 2004; p 1:132.
(7) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 10:178 - 10:180.
(8) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:133.
(9) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:193, 12:219-220.
(10) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:123-6:137.
(11) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:107-6:122.
(12) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:4-9:94.
(13) - Atomic Mass Data Center. http://amdc.in2p3.fr/web/nubase_en.html (accessed July 14, 2009).
(14) - Silberberg, Martin S. Chemistry: The Molecular Nature of Matter and Change, 4th ed.; McGraw-Hill Higher Education: Boston, MA, 2006, p 965.
(15) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 14:17.
(16) - Morgan, John W. and Anders, Edward, Proc. Natl. Acad. Sci. USA 77, 6973-6977 (1980)
(17) - Brownlow, Arthur. Geochemistry; Prentice-Hall, Inc.: Englewood Cliffs, NJ, 1979, pp 15-16.